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Keyair · 11-20-2015, 04:51 PM

Yes Brad, Transmission temp gauges rock!

Peter, that extra hole will only likely become active 500 miles from home, at night, in a storm, in some desolate place, with no cell coverage...

Keyair · 11-20-2015, 05:03 PM

Here the matching trans temp gauge I found on Ebay a couple of years back.
I hope the sender is the right size!

bkahler · 11-20-2015, 05:19 PM

I've got the same gauge but don't have a sending unit. How much do you want for the sending unit?

Keyair · 11-21-2015, 08:58 PM

Quote:

Originally Posted by bkahler

I've got the same gauge but don't have a sending unit. How much do you want for the sending unit?

Brad, I had a brain fart and could not remember the make of gauges we have....
Had to sift thru 40 pages of my own thread to find it!

Teleflex!

Armed with that, I found this, which looks just like the one I was sent with my gauge.
Boat Water Oil Temp Sending Unit Sender Single Faria Teleflex Gauge 240 Degree | eBay

But if you search 1/8th NPT oil temp sender, you find thigs like this, that should work, and is cheaper.
Water Oil Temp Temperature 1 8 NPT Electrical Sender Sending Sensor Unit | eBay

bkahler · 11-22-2015, 05:14 AM

Quote:

Originally Posted by Keyair

Brad, I had a brain fart and could not remember the make of gauges we have....
Had to sift thru 40 pages of my own thread to find it!

Teleflex!

Yep and I've got boxes full of the various Teleflex gauges

Quote:

Armed with that, I found this, which looks just like the one I was sent with my gauge.
Boat Water Oil Temp Sending Unit Sender Single Faria Teleflex Gauge 240 Degree | eBay

The problem with this sending unit is its for 120-240 degree and the oil temp gauges are 160-320 degree.

Does your sender have a letter on it? From what I've read it seems the transmitters have ranges and each range is assigned a letter.

Quote:

But if you search 1/8th NPT oil temp sender, you find thigs like this, that should work, and is cheaper.
Water Oil Temp Temperature 1 8 NPT Electrical Sender Sending Sensor Unit | eBay

Again, not knowing what the range is I'd be leery of buying this one.

I've experimented with a few senders trying to find the correct match for the engine coolant transmitter with minimal success. I tried calling Teleflex (owned by some other company now) and they weren't a lot of help.

I found one source that may have the transmitters and I'm going to call them Monday morning.

Brad

Keyair · 11-22-2015, 07:05 AM

OK, got it. I will find the gauge sender and see what is stamped on it.

Keyair · 11-22-2015, 10:49 AM

Brad,
If you are correct about the different range sender unit needed, then this place has us covered...
R8959: Temperature Sender: 140-320F - 1/8 NPTF - Stud , by ISSPRO - eGauges.com

Only thing I noticed is it states that it is a NPFT thread... which is diffent to the Derale threaded hole I think.

Keyair · 11-22-2015, 12:27 PM

If anyone wants a matching Teleflex transmission temp gauge...

Teleflex Transmission Oil Temperature Gauge 50760029 | eBay

PeterH-350LE · 11-22-2015, 01:32 PM

Quote:

Originally Posted by Keyair

Brad,
If you are correct about the different range sender unit needed, then this place has us covered...
R8959: Temperature Sender: 140-320F - 1/8 NPTF - Stud , by ISSPRO - eGauges.com

Only thing I noticed is it states that it is a NPFT thread... which is diffent to the Derale threaded hole I think.

whats the diff between a NPFT and NPT thread?

bkahler · 11-22-2015, 02:21 PM

Quote:

Originally Posted by Keyair

Brad,
If you are correct about the different range sender unit needed, then this place has us covered...
[/B]m/ProductDetails.asp?ProductCode=R8959]R8959: Temperature Sender: 140-320F - 1/8 NPTF - Stud , by ISSPRO - eGauges.com

Only thing I noticed is it states that it is a NPFT thread... which is diffent to the Derale threaded hole I think.

Several years ago I bought this HA157 140-320 sensor and tested It with the Teleflex transmission oil temp gauge using boiling water and the readings seemed to be close if not spot on. Personally I would rather have an actual Teleflex sending unit but I'll give this one a try. The HA157 definitely has 1/8 npt threads.

Brad

Keyair · 11-22-2015, 08:42 PM

Quote:

Originally Posted by PeterH-Airstreamer

whats the diff between a NPFT and NPT thread?

Good question, but my guess is the F stands for FINE...

I will update this when I get my derale pan...

In the meantime, I actually have some serious updates!

Today, I pulled out the fuel tank...

Its a beast... 60" x 26" x 15" and I bet weighs 80lb...
It still has some really sweet smelling gas in it too...

3x straps secured by 3/4" bolts... that Motorcycle jack to the rescue again!

And she is down.
Then undo the wires and pipes... I marked them, but they will be replaced.

Evidence of leakage?

Then attached a strap and heaved it out... its a beast.

Interestingly, I see another filler and vent tube firsther forward that are sealed up..
Maybe for the 325 or 310?

Into my pickup it went to go home.

Will be drained, cleaned and inspected.
I think I should replace the sender, and maybe even put a internal pump unit in.

martin300662 · 11-22-2015, 09:58 PM

Quote:

Originally Posted by Keyair

Good question, but my guess is the F stands for FINE...

I believe it actually stands for FUEL, there are two different ANSI sub-standards.

Basically they are the same except for the minor and major diameters ( the roundness of 'peaks' and 'troughs'), and an NPT union will have 'gaps' between the peak of one thread and trough of the other when assembled and requires some sort of sealing compound/Teflon tape, vs NPTF is specified to be 'dry', and are designed to ensure that sufficient crushing (of the entire thread form) to produce a mechanical seal.

bkahler · 11-23-2015, 05:02 AM

Martin wins the door prize!

I found this short article about NPTF threads.

After reading it it now makes me wonder if some of the leaks I've experienced over the years wasn't caused by trying to mate two dissimilar fittings. Learn something new every day!

Brad

bkahler · 11-23-2015, 05:06 AM

Steve, you're right those tanks are beasts!

You might find that the fuel tank is labeled "diesel only" somewhere on it. That's what I found on the 345 I dismantled. As for the unused openings on the side of the tank my guess is the tanks were originally for a different application and when GM/Airstream reconfigured the P30 chassis for motorhomes Airstream wanted a larger tank. GM probably used this tank on some other vehicle, possibly some other over the road vehicle.

Brad

PeterH-350LE · 11-23-2015, 06:24 AM

Quote:

Originally Posted by bkahler

Martin wins the door prize!

I found this short article about NPTF threads.

After reading it it now makes me wonder if some of the leaks I've experienced over the years wasn't caused by trying to mate two dissimilar fittings. Learn something new every day!

Brad

Ok, just to summarize what I learned today:
the Derale trans pan comes with a 1/8" NPT thread which can ONLY receive a 1/8" NPT sender unit using a sealing compound or teflon tape.
This may explain why my current sending unit is leaking despite the 150 foot torque i put on it (just kidding guys)
So the above Teleflex gauge would work if used with Brads NPT sending unit
Universal Temperature Sender Kit 140 320°F with Bushings Fits 1 8" to 1 2" NPT | eBay

bkahler · 11-23-2015, 06:41 AM

Peter, assuming the manufacturers are actually listing the correct thread designations then I agree with your assessment.

Keyair · 11-23-2015, 12:31 PM

Awesome info Peter!

My trans pan is still a week out, and still in FL, the tracking says.

Moving ahead with the tank refurbishment, I was a little concerned about what the interior of the tank would look like... rust and debris wise.
Using my Mitivac evacuater to suck out the old fuel, and it looked ok, so I was hopeful.
I scrubbed the outside, and once it was dry, pulled the sender.

It WAS working, and didnt look too bad, but I cant get a consistant OHM reading, so might replace it if its not silly money.

Looks like its a Tankcraft unit... and 90ohm, and dated 1988... so not the original!

But the pleasant surprise was the inside of the tank!
just a couple of rust spots and a little debris. The tank is baffled into 3 compartments by the look.

Will sand the exterior, treat the surface rust and prime and repaint.

bkahler · 11-23-2015, 12:41 PM

The interior of that tank is flat out amazing. Looks almost new inside!

Keep in mind your 345 came from the great plains and likely was not exposed to a lot of the exotic fuels that are in use now, especially in California. You might want to consider having your tank sealed with Red Kote Sealer. The local radiator shop uses this stuff to seal tanks and so far I'm quite please with the results. I've had multiple tanks sealed. Price was very reasonable.

Brad

Keyair · 11-23-2015, 02:40 PM

I know Brad, and am glad you think so too!
Especially when you consider it been sitting over here for 5+ years with max 20 gallons of CA gas which has lots of ethanol in it, which absorbs water like crazy. I did have Stabil in there tho.

As far as sealing it goes, I would normally agree, but...
I did my Alfa gas tank with Redcoat last year, and I am not happy with it. I did multiple cleans of that tank, as it was rusty AND had some other sealant in there...
This is what it looked like inside when I started...

After 3 cleans, it looked like this... you can see the previous yellow coating coming off...

I spent hours and hours on it.. pressure washing, and tumbling it until it looked ok(new tanks were unobtainium or you have to mod a later tank).
I then followed the Redcote instructions to the letter, 2 coats and left the tank to dry for 2 months before putting it back in...

Now, a year later I am on my 5th tank filter, full of sediment, and the gas comes out stained red...
Maybe I did something wrong, but I am not going to risk it.
Also, the plan is to put a diesel in sometime in the future, so I would flush and inspect it then and see if it needs sealing.

Anyway, after hitting it with the DA sander, chemically treating the minor surface rust, and wiping it down with acetone, I slapped on the first coat of silver hammer Rustoleum.

I did the exterior of my 73 K10 saddle gas tanks about 10 years ago and they still look great.

bkahler · 11-23-2015, 04:17 PM

Steve, I wouldn't try to coat the tank myself. I'm of the opinion that prior to sealing it should be acid dipped to de-rust the tank before it is sealed. That's why I take mine to the local radiator shop where they dip it then seal it. I don't think any other process, as you found out the hard way, would work well enough to prep the tank for sealer.

The gas tank for my 51 Dodge pickup cost about $70 for the complete clean and seal.

Have you measured the tank opening diameter for the sender yet? I'm curious as to what that dimension is.